In a Long Term Evolved (Long Term Evolved, abbreviated as LTE) system put forward by the Third Generation Partnership Project (Third Generation Partnership Project, abbreviated as 3GPP) organization, downlink transmission channels mainly include: physical downlink control channel (Physical downlink control channel, abbreviated as PDCCH) and physical downlink shared channel (Physical downlink shared channel, abbreviated as PDSCH), which are used to transmit downlink control information (Downlink control information, abbreviated as DCI) and downlink data respectively. In an LTE Rel.8 system, the downlink data may be transmitted by using different transmission modes. Each transmission mode may include two DCI formats (Format). In the DCI format, each control bit may indicate control information required by a PDSCH data transmission scheme under a specific transmission mode. A network side configures a specific data transmission mode for each terminal in a semi-static manner. Under a specific transmission mode, each control bit of the DCI format is configured dynamically so that the control information required by the PDSCH data transmission scheme is indicated to a user. The terminal blindly detects each control bit of the two DCI formats and obtains the control information required by the PDSCH data transmission scheme of the terminal.
In the DCI format defined by the LTE Rel.8 system, the DCI format 2 and DCI format 2A support a transmission control indication of two codewords (Codeword, abbreviated as CW). Control bits in the transmission control indication include: a transmission control bit of a transmission block (Transmission Block, abbreviated as TB), and a control bit of indication information indicating whether to swap a corresponding relationship between the transmission block and the codeword (namely a “TB to CW swap flag” control bit), and so on. Transmission control bits of each transmission block includes: a modulation and coding scheme (Modulation and Coding Scheme, abbreviated as MCS) indication bit, a new data indicator (New data indicator, NDI) bit, and a redundancy version (Redundancy version, abbreviated as RV) indication bit. The network side correspondingly indicates the control information of the two transmission blocks in the foregoing control bits. The terminal detects each control bit in the DCI format to determine the control information of the current PDSCH data transmission.
In the process of implementing embodiments of the present invention, the inventor finds that in the prior art: Efficiency of using the control bits is improper in a frame structure that supports transmission of two codewords, therefore a technical defect that efficiency of using an overhead required for transmitting control information is low exists.